Here's some stuff I came across that I found useful or interesting for running a game:
Solo Gaming by Tiny Solitary Soldier - how to play an adventure solo with 2d6 and not much else. Apart from solo gaming, I really like this for figuring out what NPCs do when the PCs are not around. For example, I have a NPC that got scammed badly by my PCs and I don't want to just decide what happens to him. So after five minutes with this, I have a little story that may give me some more story hooks as well.
Creating Meaningful Choices as a GM by DM Fiat - how to give your players a choice that actually means something for the outcome of the story. Love the example.
The Big List of RPG Plots - what is says on the box
Random Tables by Tales of the Grotesque and Dungeonesque, not just for fantasy games. I like the Random Cabaret Generator in particular.
RoleplayingTips.com - again, exactly what it says on the box
Abdulafia Random Generators - anything from plots to places to names
Rory's Story Cubes by Black Vulmea - about using these nifty story dice as a storytelling help. I've used those cubes (just the standard set) to come up with adventure ideas and character concepts, they are a great help to get the imagination running.